I recently purchased a 2001 FXDX Dyna Super Glide Sport from a very good friend and I couldn't be happier.

It has one sticky issue however, it occasionally misfires.

I am unfortunately not a gear head (but am learning and am eager) and this is my first HD (had a honda previously) so I'm not sure what to do.

I have replaced the plugs (HD OEM plugs, gaped properly), and it still does the same thing. The guy that I bought it from said it's always done it since he had it (second owner) and has always wanted to take it into HD to have them put it on a Dyno and get it rejetted to see if that can address the issues, his thoughts were that maybe the timing is a little off.

It tends to do it when you are idling and typically sitting at a stop light or stopping. It also does it when it's cooler outside (was 45deg this morning) but after the engine has warmed up.

Normally I can recover from the misfire, the engine doesn't actually stall, but this morning i was turning the corner, clutch pulled in, engine idling and it stalled mid turn. I was able to restart it during the turn and take off like usual but it surprised the hell outta me.

It currently has stock pipes that have had the baffles removed, has a Youst (sp?) Power Tube in the carb, and screaming eagle air filter on it.

I have an appointment with a local HD dealer to get it on the Dyno next week, but was looking if anyone might have an ideas other than that.

Oh, one other thing I might add if it makes a difference... When starting the bike, I typically pull the enricher out all the way, twist the throttle a little and then back to idle, then hit the ignition. The bike always starts right up. I let it idle for about 20-30 seconds then start off fairly slowly, go about 1/2 mile and push the choke in and just use the throttle to keep it going till it warms up enough to idle on it's own.

Sounds like the carb is starving for gas which is always possible as soon as the exhaust is modified. I would try it the bike for a bit with the choke partially cloded so it runs richer and see if there's a differnce. Also it sounds like its starving on lower speeds meaning the main jet wouldn't be kicking in fully yet. Another sure test would be get the bike cruising 60 - 65 mph and pull in the clutch and hit the kill switch at the same time , pull over to side of the road , pull the spark plugs and check the color, see if there a nice tan color being normal.

To me this sounds "electrical", I would start replacing the ignition wires & caps (I think thats what you call them in english, I'm talking about the wires that connect to your spark plugs ) .

would electrical be that intermittent? the mis-fire only occurs occasionally, and normally only while idling down, never while speeding up or going at a level speed.

I've also noticed that if I sit idle for a while and rev the motor (it's new to me, i like the way it sounds ) it's more likely to do it.

__________________
---------------------------
Political Correctness is a doctrine, fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

Sounds like the carb is starving for gas which is always possible as soon as the exhaust is modified. I would try it the bike for a bit with the choke partially cloded so it runs richer and see if there's a differnce. Also it sounds like its starving on lower speeds meaning the main jet wouldn't be kicking in fully yet. Another sure test would be get the bike cruising 60 - 65 mph and pull in the clutch and hit the kill switch at the same time , pull over to side of the road , pull the spark plugs and check the color, see if there a nice tan color being normal.

Man, I don't know if i'm at the comfort level to do something like that, to be quite honest (driving down the highway and killing it like that). I'm still somewhat of a noob, but that being said, I'm not opposed to doing that, just gotta get the balls to do it.

When I first got it, I put new plugs in it, the plugs i took out had some black on them, but not too bad. (Initially i though maybe I fouled a plug). Changing the plugs didn't make a difference at all

Would having the bike rejetted possibly fix this problem or am I barking up the wrong tree with putting it on the Dyno to have it tuned up and rejetted? I know that it's never had that done, so it can't hurt, but other than the misfire I'm actually quite happy with the way the bike performs.

Thanks again for the responses!

Kip

__________________
---------------------------
Political Correctness is a doctrine, fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

Man, I don't know if i'm at the comfort level to do something like that, to be quite honest (driving down the highway and killing it like that). I'm still somewhat of a noob, but that being said, I'm not opposed to doing that, just gotta get the balls to do it.

When I first got it, I put new plugs in it, the plugs i took out had some black on them, but not too bad. (Initially i though maybe I fouled a plug). Changing the plugs didn't make a difference at all

Would having the bike rejetted possibly fix this problem or am I barking up the wrong tree with putting it on the Dyno to have it tuned up and rejetted? I know that it's never had that done, so it can't hurt, but other than the misfire I'm actually quite happy with the way the bike performs.

Thanks again for the responses!

Kip

Checking the plugs color on the hiway will give you a definate answer as to wether you need rejetting.
Killing the engine spark at hiway speed will give a real-time result as to what the motor was doing at that exact moment. killing the engine at hi speed is no big deal just make sure you pull the clutch in right after hitting the kill switch and don't shift down, you can shift back to neutral after your pulled over stopped.

Register Now

In order to be able to post messages on the V-Twin Forum : Harley-Davidson Motorcycle Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:

Password

Please enter a password for your user account. Note that passwords are case-sensitive.

Password:

Confirm Password:

Email Address

Please enter a valid email address for yourself. WE WILL SEND A CONFIRMATION EMAIL TO THE ADDRESS YOU PROVIDE. If the email address is NOT VALID, you will not be given access to the system!

Email Address:

Log-in

User Name

Remember Me?

Password

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.